Ventilated sight rib mount on a shotgun barrel

ABSTRACT

A metal sight rib has in its bottom a dovetail groove received with a slide fit on dovetail projections on spaced and aligned upright posts on a shotgun barrel, with the groove having wedge formations bearing against the opposite ends of the dovetail projections on selected posts for locking the sight rib to the latter, and a method of thus mounting the sight rib, involving sliding the same into fit with the dovetail projections on the posts, and crimping the sight rib inwardly at the opposite ends of the dovetail projections on selected posts for wedging the sight rib to the ends of these projections.

United States Kt [1 1 [111 3,727,339 Snyder 1 1 Apr. 17, i973 15 1 VENTILATED SIGHT RIB MOUNT ON 3,325,937 6/1967 Morrow ..33/47 x A SHOTGUN BARREL 3,083,453 4/1963 Reynolds et al. ..29/509 UX [75] Inventor: george R. Snyder, Woodbridge, Primary Examiner Roben B Hun onn.

Attorney-Walter Spruegel [73] Assignee: The Marlin Firearms Company,

' North Haven, Conn. [5 7] ABSTRACT Filedi P 1971 A metal sight rib has in its bottom a dovetail groove [21] Appl No Z 130,887 received with a slide fit on dovetail projections on spaced and aligned upright posts on a shotgun barrel, with the groove having wedge formations bearing U.S. s "33/233, against the opposite ends of the dovetail projections [51] CL 3 1/42 8 1/00, F41: 21/00 on selected posts for locking the sight rib to the latter, [58] Field of Search ..33/47; 29/509; and a method of thus mounting the Sight rib involving 42/76 sliding the same into fit with the dovetail projections on the posts, and crimping the sight rib inwardly at the [56] References cued opposite ends of the dovetail projections on selected UNITED STATES PATENTS posts for wedging the sight rib to the ends of these projections. 3,171,226 3/1965 Into ..33/47 X 3,017,966 1/1962 Betz ..29/509 X 2 Claims, 12 Drawing Figures PATENTED 3.721319 Eli BY if 059/ ATT NE VENTILATED SIGHT RIB MOUNT ON A SHOTGUN BARREL This invention relates to sight ribs for shotguns, and

more particularly to mounted sight ribs of ventilated type on shotgun barrels.

Shotgun barrels become quite hot during periods of firing, and heat waves emanating therefrom interfere with the line of sight just above the barrel. To overcome this difficulty, sight ribs have been attached to barrels in spaced relation thereabove to permit air to circulate therebetween, with the ribs interrupting the shimmering heat waves from the barrels along the line of sight and being themselves maintained relatively cool by air circulating about them. Of course, this condition brings about differential thermal expansion of the barrel and sight rib, and to keep the sight rib true under all conditions, including heat-up of the barrel, the sight rib is mounted, customarily on spacer posts along the barrel, sufficiently firmly to withstand recoil of the barrel on firing, yet with sufficient freedom to give way to natural thermal expansion longitudinally thereof and entirely independently of the thermal ex pansion of the barrel. To so mount sight ribs on spacer posts along barrels, recourse is had to various known expedients which, while generally satisfactory, are, however, complex, more or less, and involve considerable cost.

It is a primary object of the present invention to provide a barrel-mounted sight rib of ventilated type which is of exceeding structural simplicity and involves particularly low cost, yet remains entirely accurate and true under all conditions, including heat-up of the barrel and recoil of the same on firing.

It is another object of the present invention to provide a barrel-mounted sight rib of ventilated type, of which the spacer posts on the barrel have anchor tops with opposite undercut sides, and the sight rib is a metal channel in substantial form-fit with the anchor tops of the posts so that the channel is interlocked therewith against lateral removal therefrom, but has sufficient freedom of longitudinal movement thereon to undergo natural thermal expansion and contraction and remain unaffected by thermal expansion and contraction of the barrel, and the channel is further locked to the anchor tops of the posts against any longitudinal give thereon on recoil of the barrel when firing, by formations in the channel which lock the latter to the opposite ends of the anchor top of the least one post, and preferably to the opposite ends of the anchor tops of a few of the posts at selected locations at which the thus locked channel retains its freedom for natural thermal expansion and contraction. With this arrangement, the firm mount of the side rib is achieved solely by the posts and the sight rib, and without any additional parts such as pins or screws, save perhaps one pin for securing the sight rib to one post for added firmness of the mount of the sight rib to withstand any, and even particularly severe, recoil ofa barrel on firing.

It is a further object of the present invention to provide a barrel-mounted sight rib of ventilated type in which the aforementioned lock formations in the channel are wedge formations which bear against the opposite ends of the anchor tops of the posts at the selected locations. With this arrangement, the wedgetype lock of the channel to the selected posts affords the characteristic firm lock of wedges, yet these wedge formations in the channel may have very small wedge angles which, while still affording a firm lock for all in-, tended purposes, also afford the channel a measure of longitudinal give to its natural thermal expansion and contraction and also to thermal expansion and contraction of the barrel. This latter feature is an important one, in that the choice of posts to which to lock the channel in this fashion may even be a random one, and the mount of the channel would be entirely satisfactory even if the channel were thus locked to all posts.

Another object of the present invention is to devise a means of mounting a sight rib of ventilated type on a barrel, according to which the aforementioned channel is simply slid onto the anchor tops of the spacer posts on the barrel, whereupon at least one, and preferably both, of the opposite legs of the channel is or are slightly displaced inwardly in the vicinity of the ends of the anchor tops of the posts at the selected locations for the formation of the aforementioned wedge formations in the channel and simultaneous finish of the mount of the sight rib, unless additional recourse is had to pinning the channel to one of the posts. This means is exceedingly simple and quick and entails a lowest possible cost, involving mere easy slide-on of the channel onto the spacer posts, and slight inward crimping of the channel legs of the selected spacer posts, with such crimping of the channel legs being done either in a fixture in one operation, or with a hand tool successively at the selected spacer posts. Such crimping of the channel legs with a hand tool is, of course, entirely feasible, since this requires little force, and an attendant will know by feel alone how much force to apply to obtain a satisfactory mount of a sight rib by thus crimping or deforming the channel legs to an extent which is imperceptible to a casual viewer.

Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

FIG. 1 is a side view of a shotgun with a barrelmounted ventilated sight rib that embodies the invention;

FIGS. 2 and 3 are enlarged fragmentary sections through the shotgun substantially along the lines 22 and 3-3, respectively, of FIG. ll;

FIG. 4 is an enlarged fragmentary section through the mounted sight rib substantially along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary section through a sight rib and a modified mount thereof;

FIG. 6 is a fragmentary section through a sight rib and a further modified mount thereof;

FIG. 7 is a fragmentary side view of a barrel-mounted ventilated sight rib embodying the invention in another modified manner;

FIGS. 8 and 9 are fragmentary sections taken on the lines 88 and 9--9, respectively, of FIG. 7;

FIG. 10 is a fragmentary side view of a barrelmounted ventilated sight rib embodying the invention in a further modified manner; and

FIGS. 11 and 12 are fragmentary sections taken on the lines ll! 1 and 12l2, respectively, of FIG. 10.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral designates a shotgun having a barrel assembly 22, including a barrel 24, and a breech assembly 26, including a breech housing 28.

Suitably mounted on the barrel 24, as by well-known projection welding, for example, are a plurality of Iongitudinally spaced and aligned upright spacer posts 30 having anchor tops 32 with opposite undercut sides 34 (FIG. 3). Carried by the spacer posts 30 is a sight rib 36 which is a metal bar of a channel shape for its reception by the anchor tops 32 of the posts 30 with a slide fit, whereby the sight rib 36 is spaced from the barrel 24 and, hence, is a ventilated sight rib. The reception by the anchor tops 32 on the posts 30 of the channelshaped sight rib 36 with a slide fit locks the latter to the barrel 24 against lateral removal therefrom, but not against longitudinal displacement on the barrel.

To lock the sight rib 36 also against longitudinal displacement on the barrel under all conditions, including recoil of the shotgun when firing, the sight rib 36 is cammed or wedged to the anchor tops 32 of selected ones of the posts 30, which may include all, or less than all, of the posts 30. To this end, the sight rib 36 is within its channel provided with cam or wedge formations 38 which bear against the opposite ends 40, and more particularly against the opposite end edges, of the anchor tops 32 on the selected posts 30 (FIG. 4) and thus lock the sight rib to these posts against longitudinal displacement thereon. In thus wedging the sight rib to the selected spacer posts, there is also taken up all play between them, including play of the sight rib to and from the barrel 24.

For reasons becoming apparent hereinafter, including a secure lock of the sight rib against longitudinal give under any, and even particularly severe, recoil of the shotgun when firing, the firm mount of the sight rib is preferably enhanced by pinning the latter to one of the posts, such as the post 30', for example, where a pin 42 locks the sight rib to the anchor top on the post 30 (FIGS. land 2).

For clearer illustration, the wedge formations 38 in the channel of the sight rib 36 are shown at a considerable wedge angle. In reality, the angles of these wedge formations 38 are preferably smaller than shown, and they are advantageously so small that, while the combined force with which the sight rib is wedged to the posts will lock the sight rib against longitudinal displacement on the barrel on recoil of the shotgun when firing, these wedge formations in the sight rib at the individual posts 30 permit that very slight longitudinal give between them which the sight rib requires for its own natural longitudinal thermal expansion and contraction and also to remain unaffected by the differential thermal expansion and contraction of the barrel 24.

The anchor tops 32 on the spacer posts 30 may be simple dovetail projections, and the channel in the sight rib 36 may be formed by a dovetail groove 44 in the bottom surface 46 of this rib (FIG. 2), with the groove 44 conveniently extending throughout the length of the rib. The wedge formations 38 are in this instance provided on the opposite inclined sides 48 of the dovetail groove 44 in the sight rib 36 (FIGS. 3 and 4). It is, of course, also feasible to provide the wedge formations 38a on only one of the opposite inclined sides 48a of the dovetail groove 44a in the sight rib 36a for locking the latter to the ends 40a of the dovetail projections 32a of posts 30a (FIG. 5).

While for reasons explained hereinafter, it is greatly preferred to provide the wedge formations 38 on both sides 48 of the dovetail groove 44 in the sight rib 36, it is feasible to provide these wedge formations, not on either of these groove sides 44 but, instead, on the bottom surface of the dovetail groove. Thus, FIG. 6 shows an arrangement in which the wedge formations 38b are provided on the bottom surface 50 of the dovetail groove 44b in the sight rib 36b, with these wedge formations 38b locking the sight rib to the ends 40b of the dovetail projections 32b on posts 30b on a barrel 24b.

Involved in the described featured amount of the ventilated sight rib is an also featured method of thus mounting the sight rib, according to which the rib is with its channel slid into fit with the anchor tops of the posts on the barrel, whereupon the sight rib is at the opposite ends of the anchor tops of selected posts crimped inwardly to wedge the rib to the ends of the anchor tops of these selected posts. Thus, in the preferred rib mounting of FIGS. 1 to 4, the slid-on sight rib 36 is, by the prongs 52 of a hand or automatic tool, for example, (FIG. 4), crimped inwardly at the opposite sides of the rib and preferably within the depthwise confines of the dovetail groove 44 therein (FIG. 3), to form the wedge formations 38 (FIG. 4). For reasons explained hereinbefore, the wedge angles of the wedge formations 38 are preferably quite small, and this is further advantageous in that the crimps in the sight rib, caused by the tool prongs 52 or another appropriate tool, are virtually imperceptible, meaning also that comparatively little force is involved in thus crimping the sight rib. Of course, the same method prevails in providing the modified rib mounts of FIGS. 5 and 6, with a suitable pressure tool being applied to crimp one side of the sight rib in FIG. 5, or to crimp the bottom wall of the channeled sight rib in FIG. 6. Further, the method applied for mounting the sight rib in FIGS. 1 and 2 also includes pinning the sight rib to one of the posts.

While in the preferred rib mount of FIGS. 1 to 4, the sight rib has in its bottom surface a dovetail groove, FIGS.'7 to 9 show a rib mount in which the metal sight rib 36c is a U-shaped channel (FIG. 8), the opposite legs 60 of which are along and for some distance beyond the dovetail projections 32:: on the posts 300 inclined at 62 into slide fit with the dovetail projections 32c (FIGS. 7 and 9), with these leg portions 62 being, by crimping or in any other suitable manner, thus inclined with respect to the remaining parallel portions of the legs 60. The described method also prevails in this instance, in that the sight rib is slid into fit with the dovetail projections on the posts, whereupon the inclined leg portions 62 of the rib are crimped inwardly slightly further near the opposite ends of the dovetail projections on the selected posts, as at 64, for example (FIG. 7).

Reference is finally had to FIGS. 10 to 12 which show a rib mount that is identical with that of FIGS. 7 to 9, except that the sight rib 36d is primarily a substantially flat bar (FIG. 1 I having only along and for some distance beyond the spacer posts 30d inclined side flanges 64 in slide fit with the dovetail projections 32d on the posts, with these side flanges 64 being, near the opposite ends of the dovetail projections on selected posts, crimped slightly inwardly to wedge the sight rib to the ends of these dovetail projections.

What is claimed is:

1. A barrel-mounted sight rib, comprising a shotgun barrel with longitudinally spaced and aligned upright posts having anchor tops in the form of dovetail projections of uniform section and opposite end edges, and a pressure-deformable metal sight rib having a bottom surface with a dovetail groove therein in longitudinal slide-fit interlock with said post projections, said rib having on opposite sides outer minute depressions forming in said groove pairs of opposite uninterrupted wedge surfaces of longitudinal extent of which the wedge surfaces of successive pairs are intermediate their longitudinal extent in contact with the opposite end edges of selected post projections, respectively, and the wedge surfaces of each successive pair have opposed wedge angles for wedging engagement with the opposite end edges of the associated post projection, with the wedge angles of said wedge surfaces being so small that said rib is locked to said selected posts against longitudinal displacement thereon on recoil of the barrel when firing, but permits said rib to give way to differential thermal expansion and contraction between said rib and barrel without lateral distortion of said rib.

2. A barrel-mounted sight rib as in claim 1, in which said metal rib is pinned to one of said posts. 

1. A barrel-mounted sight rib, comprising a shotgun barrel with longitudinally spaced and aligned upright posts having anchor tops in the form of dovetail projections of uniform section and opposite end edges, and a pressure-deformable metal sight rib having a bottom surface with a dovetail groove therein in longitudinal slide-fit interlock with said post projections, said rib having on opposite sides outer minute depressions forming in said groove pairs of opposite uninterrupted wedge surfaces of longitudinal extent of which the wedge surfaces of successive pairs are intermediate their longitudinal extent in contact with the opposite end edges of selected post projections, respectively, and the wedge surfaces of each successive pair have opposed wedge angles for wedging engagement with the opposite end edges of the associated post projection, with the wedge angles of said wedge surfaces being so small that said rib is locked to said selected posts against longitudinal displacemEnt thereon on recoil of the barrel when firing, but permits said rib to give way to differential thermal expansion and contraction between said rib and barrel without lateral distortion of said rib.
 2. A barrel-mounted sight rib as in claim 1, in which said metal rib is pinned to one of said posts. 